JP3910060B2 - Broaching and holding device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an inner surface broaching work holding device for a high-hardness material hollow cylindrical workpiece, and more particularly to a broaching method with a high cutting speed of 10-60 m / min for a high-hardness material hollow cylindrical workpiece of HRC20 or higher.
[0002]
[Prior art]
It is well known that the inner cylinder broaching process for holes such as spline holes in hollow cylindrical workpieces does not make the cylindrical diameter of the hollow cylindrical workpiece straight, for example, issued on June 10, 1970. In Corona's “Newly Revised Precision Handbook”, edited by the Precision Machinery Society, page 357, “5.7.4 Broaching accuracy”, it appears prominently when the wall thickness is not the same, but it is hollow and cylindrical even if the wall thickness is uniform. It has been introduced that for thin-walled workpieces, the cylindricity of the workpiece diameter does not become straight.
[0003]
In the conventional inner surface broaching of a hollow cylindrical workpiece, as shown in FIG. 5, the workpiece receiver 2 is fixed to a bolster 3 fixed to a table 4 of a broaching machine, and the inner diameter is slightly larger than the outer diameter of the workpiece 1. The workpiece 1 is attached to the workpiece receiver 2 and the inner surface broaching of the workpiece is performed. The workpiece receiver 2 is replaced when the outer diameter of the workpiece 1 changes. As shown in FIG. 5, when the guide part 51 of the broach 5 is inserted into the pilot hole 6 of the work 1 from above, the work 1 is displaced so as to be concentric with the broach 5. After the insertion, the broach 5 moves downward, and the work inner diameter is sequentially cut by the cutting edge 52 following the guide portion 51. As described in the above-mentioned "New Revised Precision Handbook", page 357, section 5.7.4, the broached inner diameter is generally a trumpet shape with a large inlet side and a small outlet side, or a drum shape with a large inner diameter at the center. . The reason why it becomes distorted is considered to be that a force is applied in the circumferential direction of the workpiece at the start of cutting, and the side surface of the workpiece is deformed (increases in the circumferential direction). When inner surface broaching is performed by the method shown in FIG. 5, a drum shape with a large inner diameter at the center is obtained.
[0004]
[Problems to be solved by the invention]
Thus, in the internal broaching of a conventional hollow cylindrical workpiece, the inner diameter of the workpiece is not straight, but when the wall thickness is large as in the workpiece shown in FIG. 5, the cutting speed is less than 10 m / min. In the case of low-hardness material workpieces of less than HRC20, there was no problem because it is generally within the allowable range in terms of product functions. However, in high-speed broaching with a cutting speed of 10 m / min or higher, especially at a cutting speed of 40 to 60 m / min, the amount of spreading on the side of the workpiece has increased, and the machining accuracy has deteriorated. In particular, when the hardness of the material is higher than HRC20, the broach cutting load increases and the amount of spread on the side of the workpiece increases, resulting in poor machining accuracy. In machining accuracy, the workpiece size tends to have a smaller inner diameter near the inlet and outlet and smaller than the broach finish size. Naturally, the straightness of the workpiece machining surface in the broach pulling direction also deteriorates.
An object of the present invention, the inner surface broaching at high cutting speeds a high hardness material hollow cylindrical workpiece such HRC20 or more such 10 to 60 m / min, press spread amount of the work side is small, the machining accuracy, workpiece dimensions In the broaching and holding device and broach , the inner diameter in the vicinity of the inlet and outlet is smaller than the inner diameter of the central part and does not tend to be smaller than the broach finish dimension, and a high accuracy straightness of the workpiece processing surface in the broach drawing direction can be obtained. It is to provide a processing method.
[0005]
[Means for solving the problems]
Thus the present invention, the inner surface broaching of the hollow cylindrical workpiece, the inlet and outlet sides outer peripheral surface of the workpiece, from the opposite two directions or more directions of the work, be consistent with the inlet side and outlet side outer peripheral surface this inner to pressurize each pressing surface having a peripheral surface and outer peripheral surface other than the inlet and outlet sides are described above by providing a broaching holding apparatus being characterized in that as no pressurized that Solved the problem of the invention.
[0006]
【The invention's effect】
With such a configuration, in the inner surface broaching of a high-hardness material hollow cylindrical workpiece such as HRC20 or more at a high cutting speed of 10 to 60 m / min, the amount of expansion on the workpiece inlet side and outlet side surface is small , and in machining accuracy, In the workpiece dimensions, the inner diameter near the inlet and outlet is smaller than the inner diameter of the central part and does not tend to be smaller than the broach finish dimension, and it is possible to obtain a high-accuracy straightness of the workpiece processing surface in the broach pulling direction. Thus, a broaching and holding device capable of obtaining the same workpiece machining size as that of the present invention is provided. In addition, the wear of the blade of the broach was reduced and the life of the broach was extended.
[0007]
Pressure to pressure can be obtained by about 20-50% of the broach cutting load, the more accurate straightness. The pressurizing force is not effective when it is about 20% or less of the broach cutting load, and a load exceeding 50% is not necessary, and there is a possibility of deforming the workpiece. Therefore, about 20 to 50% of the broach cutting load is desirable.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
1A and 1B show a broaching processing holding device according to an embodiment of the present invention, in which FIG. 1A is a schematic top view, and FIG. 1B is a schematic cross-sectional view of a main part taken along line BB in FIG. Broaching holding device of the present invention embodiment, the inner surface broaching of the hollow cylindrical workpiece 10, to the inlet side 10a and outlet 10b outer peripheral surface of the workpiece 10, the inlet and outlet sides from the facing four directions of the workpiece 10 The pressurizing surface 11 having inner peripheral surfaces 11a and 11b that coincide with the outer peripheral surface is pressurized using a hydraulic cylinder 12 , and the outer peripheral surfaces other than the inlet side and the outlet side are not pressurized. The 2 is a bolster that is fixed to the table 4 of the broaching machine. In the embodiment of the present invention, the pressurizing surface 11 is pressed from the four opposing directions of the workpiece 10. However, in the case of a workpiece having a small outer diameter, the pressurizing surface 11 may be pressed from the two opposing or three directions.
[0009]
With such a configuration, in the internal broaching of a high-hardness material hollow cylindrical workpiece such as HRC20 or higher at a high cutting speed of 10 to 60 m / min, the amount of spread on the workpiece inlet side and outlet side surface is small , and the workpiece accuracy is reduced . inlet and the inner diameter near the exit is smaller than the inner diameter of the central portion is dimensioned, not prone to be smaller than the broach finished size, it is possible to obtain a high accuracy of straightness of the workpiece machining surface brooch drawing direction, and lingering finished size A broaching holding device and a broaching method capable of obtaining the same workpiece machining size are provided.
[0010]
The pressurizing force is not effective when it is about 20% or less of the broach cutting load, and a load exceeding 50% is not necessary, and there is a possibility of deforming the workpiece. Therefore, about 20 to 50% of the broach cutting load is desirable. In the embodiment of the present invention, the broach cutting load is set to about 30%.
[0011]
【Example】
Fig. 2 is a top view of the workpiece used in the workpiece straightness situation test at the time of high-speed broaching shown in Fig. 3 and Fig. 4. Parallel 4 splines with outer diameter Φ68mm, thickness 36mm, pilot hole thickness 12mm, Φ48mm Have. NC high-speed broaching machine, cutting oil: unicut chinen, measuring instrument: straightness measuring instrument, broach rake angle is 15 °.
Fig. 3 shows the shape of Fig. 2, using a S45C raw material workpiece with hardness HRC20, and performing parallel 4-spline internal broaching at a high cutting speed of 40m / min. (A) Broaching of Fig. 1 Work piece of parallel 4 spline of Φ48mm in the BB line direction of the work of FIG. 2 when not using the holding device and applying pressure using the broaching holding device of FIG. The straightness measurement result is shown.
The straightness of the workpiece was 6 μm to 8 μm when the broaching and holding device of FIG. 1 was not used, but 3.5 μm to 5 μm when the pressure was applied using the broaching and holding device of FIG. As a result, the processing accuracy is improved and the life of the broach can be extended.
Fig. 4 shows the shape of Fig. 2 when using an SCM415 workpiece with hardness HRC60 and performing parallel 4-spline internal broaching at a high cutting speed of 60m / min. When the pressure is not applied without using the workpiece, and (b) when the workpiece is pressurized using the broaching holding device shown in FIG. 1, the workpiece of a parallel 4-spline workpiece of Φ48 mm in the BB line direction of the workpiece shown in FIG. The straightness measurement result is shown.
The straightness of the workpiece was 12 μm when no pressure was applied without using the broaching processing holding device of FIG. 1, but when the pressure was applied using the broaching processing holding device of FIG. 1, the processing accuracy was improved to 5 μm. The life of the broach can be extended.
[Brief description of the drawings]
1A and 1B show a broaching processing holding device according to an embodiment of the present invention, in which FIG. 1A is a schematic top view, and FIG. 1B is a schematic cross-sectional view of an essential part taken along line BB in FIG.
FIG. 2 is a top view of a workpiece used for a workpiece straightness situation test during high-speed broaching shown in FIGS. 3 and 4. FIG.
[Fig. 3] (a) Broach shown in Fig. 1 when using an S45C raw material workpiece of hardness HRC20 with the shape shown in Fig. 2 and performing parallel 4-spline internal broaching at a high cutting speed of 40m / min. The workpiece straightness measurement result when not pressurizing without using the processing holding device and when (b) pressurizing using the broaching processing holding device of FIG. 1 is shown.
Fig. 4 (a) Holding broaching of Fig. 1 when using an SCM415 workpiece of hardness HRC60 with the shape shown in Fig. 2 and performing parallel 4-spline internal broaching at a high cutting speed of 60m / min. The workpiece straightness measurement results when not pressurizing without using the apparatus and when (b) pressurizing using the broaching holding apparatus of FIG. 1 are shown.
FIG. 5 is a schematic cross-sectional view showing internal broaching of a conventional hollow cylindrical workpiece.
[Explanation of symbols]
5. Brooch
10. ・ Hollow cylindrical work
10a ・ ・ Outer peripheral surface of workpiece entrance side
10b ..Outer peripheral surface of workpiece outlet side
11.Pressurized surface
11a ..Pressure surface inner peripheral surface that coincides with workpiece outer peripheral surface
11b ..Pressure surface inner peripheral surface that coincides with workpiece outer peripheral surface

Claims (2)

In the inner surface broaching of the hollow cylindrical workpiece, the inlet and outlet sides outer peripheral surface of the workpiece, from the opposite two directions or more directions of the workpiece, has an inner peripheral surface you meet with the inlet side and outlet side outer peripheral surface A broaching and holding apparatus characterized in that pressurization is performed on each pressurizing surface , and the outer peripheral surface other than the inlet side and the outlet side is not pressurized . The workpiece is hardened steel hollow cylinder work above HRC20, the inlet and outlet sides outer peripheral surface of the workpiece, from the opposite two directions or more directions of the work, be consistent with the inlet side and outlet side outer peripheral surface It is characterized in that machining is performed at a cutting speed of 10 to 60 m / min while applying pressure on each pressing surface having an inner peripheral surface and not pressing on the outer peripheral surface other than the inlet side and the outlet side. The broaching processing holding device according to claim 1 .

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